energize

1. To give energy to; activate or invigorate: "His childhood-father in . . . prison, factory work as a boy-both haunted and energized him" (Frank Conroy).
2. To supply with an electric current.

verb

To give or impart vitality and energy to (someone or something): exhilarate, invigorate, stimulate, vitalize. See help/harm/harmless.

Definition: activate; give more life
Antonyms: deactivate, debilitate, sap, tire, weaken, weary

Being electrically connected to a voltage source so the device is activated.

The verb has 2 meanings:

Meaning #1: cause to be alert and energetic
  Synonyms: stimulate, arouse, brace, energise, perk up
  Antonym: de-energize (meaning #1)

Meaning #2: raise to a higher energy level
  Synonyms: excite, energise